1. Field of the Invention
Aspects of the invention relate generally to communication networks, and more particularly to identification of communication routes in communication networks.
2. Description of the Prior Art
Communication networks, such as local area networks (LANs), wide area networks (WANs), virtual private networks (VPNs), and myriad others, typically provide extremely useful connectivity among large numbers of computers, personal digital assistants (PDAs), mobile communications terminals, and other devices for informational interchange. Due to the often complex topology required of a network to provide this connectivity, many possible physical paths or routes for informational transfer between any two network devices may exist. Further, the decision as to which particular path is employed for communication between a source and destination in the network may be distributed among many routers, which are devices employed to forward packets of data from a source to a destination through or between networks. Thus, determining the particular route employed for information transfer between two specific devices is often a nontrivial task.
Identification of a particular communication route between a source and a destination within one or more networks provides significant advantages in terms of facilitating network maintenance. More specifically, ascertaining the various routes employed by a network to connect any two communicating devices provides an indication of the overall topology of the network. In turn, this information allows faster identification of faulty devices within the network, as well as any “bottlenecks” adversely affecting network performance.
In networks employing Internet Protocol (IP), determining the physical route between a source and a destination is facilitated by way of an IP utility called “traceroute.” By sending a series of data packets, traceroute determines the identity of each router through which data is transferred between the source and destination, as well as the sequence or order of the routers encountered by the data. Other network protocols, such as those employed in UNIX- and Windows-based networks, provide similar utilities.
However, tracing a route through a network is complicated by the existence of multi-layer networks, which are networks utilizing two or more different network protocol layers to constitute at least a portion of a network. For example, some IP networks employ one or more optical networks to supply some of the connections between network devices. Such optical networks typically employ a communication protocol other than IP, such as the Synchronous Optical Network (SONET) protocol. However, due to limited interaction between the separate layers of the network, the optical portions of the network are not detected by the IP traceroute utility; only the IP routers are identified. As a result, a particular route through an optical portion of the network between two IP routers, which may constitute a significant portion of the route, typically remains unknown. Thus, opportunities for reconfiguring the optical connections to circumvent failed equipment or enhance performance are not exploited, making the network difficult to support and maintain.